I'm not sure what server your on but on Lindblum logs of all kinds sell rather well. The thing is that while the log itself isn't worth a ton those who need them need them in bulk. Stuff like Yew Logs and Walnut Logs are used in skilling Woodworking(as are pretty much all of the others) and make ingredients in addition. I go to the market wards quite often to sell what I have gathered and notice there are 0 Walnut Logs in the market Wards. This happens with Yew Quite often as well. The only logs I see that are never in short supply is Pine. Pretty much all the other kinds either fluctuate in having a ton available or none available.

That being the case I don't think slightly upping the % of the sweet spot would make much of a impact.